Convert N54 to A2W (Air to Water) Cooled by Air Conditioner Refrigerant

So I made a short post before but it got moved to general. To continue in a more N54 related way, I will say that I don't know a lot about dealing with refrigerants and know only a small bit about Air to Water Intercoolers.

Now if we wanted to make this inline with the existing A2A intercooler, it would have to go most likely after the FMIC and be mounted in some of the free space or inline where the chargepipe is with a bullet style A2W intercooler(Charge cooler). I'm curious what type of extra restriction this would pose on the system and what kind of extra pressure drop we would see. From the units I've looked at, they approximate about 1-1.5 PSI drop.

In Addition to putting this inline with the FMIC, we would need an A2W Heat exchanger to shed off the heat absorbed from the A2W Charge cooler, most likely mounted in front of the FMIC, in a air duct on the Driver side, or a vertically stacked FMIC/Heat Exchanger setup.

Lastly, if we decided to use the Air conditioner's refrigerant to super cool the A2w intercooler, we would need a Evaporator coil/core to cool the water.

1) How much extra refrigerant plumbing would be added and therefore how much extra refrigerant would be necessary in the system?
2) How much additional stress does this add to the current Refrigerant system with each setup
3) Does this additional stress put our compressor at risk by not being able to keep up and cool the refrigerant in the condenser and potentially sending more hot refrigerant back to the compressor?
4) What kind of extra condensation would this produce and how to manage it
5) What type of electrical is going to be required with each setup to run the A2W intercooler separately from the Cabin AC and how to turn on and off the water pump depending on if there is an A2A intercooler to cool the charge if it happens to be off

Please comment. Just searching through ebay these parts are not all that expensive.

I think designing the system ( matchig the evaporator size to compressor and condensor ) will not be an easy task since it will have such a variable load.

I would think under WOT in hot weather the water from the A2W intercooler will be so hot it will render the sytem out of efficiency.

I have been thinking about a large peltier cooling system mounted directly to the Air to Air intercooler. The cold side keeps the intercooler chilled , the hot side should be vented with passing air. Should be much easier to install , but i never seen powerfull systems based on this pricipal of cooling.

Bad idea. Main reason for air water is packaging constraints. You're adding weight and reducing efficiency. Benefit in better boost response and can pack ice (not if you're doing refrigerant). Same goes for TECs, those things are 15% efficient or so and you need 1000s of watts. Not trying to be a downer, but research more and get some basic numbers going. Hooking your AC up to your intake, driving with throttle almost shut for 5 minutes, and then getting one gear pull may be success for some, but I'd much prefer to spray meth or run NOS. Let us know how it goes though.

I think designing the system ( matchig the evaporator size to compressor and condensor ) will not be an easy task since it will have such a variable load.

Variable load as in how? Obviously you wouldn't run all the combinations at once, you'd pick either one setup or another and dial it in based on that configuration.

I would think under WOT in hot weather the water from the A2W intercooler will be so hot it will render the sytem out of efficiency.

The system turns off on WOT and only circulates water, the AC compressor stops during that time. It wouldn't make sense to run the AC while trying to go as fast as possible. This is a natural mechanic of most cars.

Originally Posted by rudypoochris

Bad idea. Main reason for air water is packaging constraints. You're adding weight and reducing efficiency.

They do a2w and a2a on Minis, I doubt they would do it if it was inefficient. Got any data/personal experience in a2w that would give insight on if it would actually be more inefficient? Hard to determine that without knowing the sizes of all the exchangers.

Hooking your AC up to your intake, driving with throttle almost shut for 5 minutes, and then getting one gear pull may be success for some, but I'd much prefer to spray meth or run NOS. .

In this video, after a run, the IAT was still below ambiant without the system running so I don't really know where you're getting 5 minutes from. Even a minute or less appears to be sufficient time to bring it back down to a reasonable temp. Even if you did another pull immediately, you still have a constant cooling effect from the A2W heat exchanger working while you're driving, even if the AC is off. For people doing highway pulls, 1 minute is enough time to catch back up, pace and honk. For people at the strip, its much longer than a minute before you get to go at it again and no hassle with loading ice at the last second.

Two intercoolers in series would make for a pretty nice restriction and pressure drop. You would lose more power from lowering turbo efficiency than you'd likely gain from the additional charge cooling. The idea to use the ac pump is interesting, but potentially dangerous. Say it's a warm day with moderate humidity. The intercooler is cooler than the dewpoint most likely, so you may get water condensing in your pipes. Unlike water injection systems it would pool, not get atomized, and be sucked in less evenly. Could cause cylinder imbalance. As for the ac compressor, I don't think it's your problem. It's just a pump and you're not expanding the system that much. You are, however, drastically increasing the demands on the refrigerant itself by adding a second evaporator core that is exposed to some major heat. This will cause the pressure in the system to raise very high, which will trip the compressor to shut off until the fluid cools. Basically... you will need a much, much larger condenser core to remove the heat from the refrigerant. Probably about 3x the size of the one on the car currently.

What are you locking to achieve here? There are likely better ways, although the idea is creative to say the least.

Two intercoolers in series would make for a pretty nice restriction and pressure drop. You would lose more power from lowering turbo efficiency than you'd likely gain from the additional charge cooling.

Quote possible. Although the A2W intercooler in mind is a bullet style cooler that wouldn't add any more bends to the system than existing and would sit some place perhaps where the current upper chargepipe resides. The tube/fin or bar/plate internals obviously would be the restriction to think about. A less restrictive A2A would be on order however, as A2W is much more efficient in terms of heat transfer.

The idea to use the ac pump is interesting, but potentially dangerous. Say it's a warm day with moderate humidity. The intercooler is cooler than the dewpoint most likely, so you may get water condensing in your pipes. Unlike water injection systems it would pool, not get atomized, and be sucked in less evenly. Could cause cylinder imbalance.

I don't think this would truly be too much of an issue. They run ice boxes and this AC system on other vehicles seemingly without issue. But it was one of my thoughts as well.

As for the ac compressor, I don't think it's your problem. It's just a pump and you're not expanding the system that much. You are, however, drastically increasing the demands on the refrigerant itself by adding a second evaporator core that is exposed to some major heat. This will cause the pressure in the system to raise very high, which will trip the compressor to shut off until the fluid cools. Basically... you will need a much, much larger condenser core to remove the heat from the refrigerant. Probably about 3x the size of the one on the car currently.

This was the problem I was referring to actually. How big is the current heat exchanger for the AC refrigerant anyway?

What are you locking to achieve here? There are likely better ways, although the idea is creative to say the least.

I live in AZ. Absolutely miserable IAT's in the summer. Imagine starting at 120*F ambient. No matter how much boost, that is never going to change. Meth can only do so much. The car can feel gutless some times during the day, and a beast again at night.

EDIT: Stock Condensor is 23X13. Where is it located? The size requirement of the condensor is dependent on the size and efficiency of the A2W intercooler. if its not pulling a ton of heat off the charge for very long, it shouldn't need to be too big. Imagine in arizona, it cools 100+* temps INSIDE the cabin with no problems at all. So perhaps two of these would suffice even if the charge cooler was pretty efficient.

Stock Condensor is 23X13. Where is it located? The size requirement of the condensor is dependent on the size and efficiency of the A2W intercooler. if its not pulling a ton of heat off the charge for very long, it shouldn't need to be too big. Imagine in arizona, it cools 100+* temps INSIDE the cabin with no problems at all. So perhaps two of these would suffice even if the charge cooler was pretty efficient.

That's a good point on the interdependence. The condenser is located in front of the radiator. My biggest issue here is the complexity to solve a simple problem. I have experience with A2W intercoolers, my friend and I built a fiero with a 3.4 DOHC engine swap with a GT3582R turbo on custom headers. Since that car is midengine, there was no good way to do an air to air setup, so we made a custom air to water. It worked well, but there's just so much added headache with that system and the temps still rose over time, especially on hot days. An air to air would have been so much better, but there just wasn't room. The only REAL advantage I saw to that setup over a good A2A was being able to use a grand total of about 18 inches of charge pipe... about one foot to the IC and about 6 inches to the TB.

Have you pursued methanol? IAT's make it harder to run full advance with pump gas and make the air charge less dense is all. If you spray meth, your effective octane goes up, helping timing. If you run E85 that helps negate the problem as well inside the engine. I also helped on a LSX build that ran twin 73mm turbo's non-intercooled. At anything over 20psi the IAT's were pegged past 250 degrees (max of the gauge) but with E85 and E98 it didn't much matter, still got full timing and made too much power to handle. We put a 1.4mm meth nozzle on each bank, and the IAT's dropped to below 120 degrees when spraying even after hard track runs in 100 degree weather and allowed for race gas to be used instead of alcohol. Maybe, you just need more methanol and less water in your mix.

Back on topic- good luck if you go this route, it will be difficult to say the least. But I always like watching the crazy projects.

I didnt read the whole thing, but are you intending on running the extra water IC from existing fluid? If so, its probably more pain than its worth. HOWEVER, there are options for other ways to do it that would be easier install, and better benefits:

That's a good point on the interdependence. The condenser is located in front of the radiator. My biggest issue here is the complexity to solve a simple problem. I have experience with A2W intercoolers, my friend and I built a fiero with a 3.4 DOHC engine swap with a GT3582R turbo on custom headers.

Always loved those cars, remember reading a lot about the northstar swaps with turbos, but it seems like I never saw any of them with good ET's. Maybe it was the transmission holding them back?

Since that car is midengine, there was no good way to do an air to air setup, so we made a custom air to water. It worked well, but there's just so much added headache with that system and the temps still rose over time, especially on hot days. An air to air would have been so much better, but there just wasn't room. The only REAL advantage I saw to that setup over a good A2A was being able to use a grand total of about 18 inches of charge pipe... about one foot to the IC and about 6 inches to the TB.

Water is supposed to transfer heat more efficiently, are you sure either your A2W charge cooler or heat exchanger wasn't insufficient? What sizes were they? was the heat exchanger mounted in the front ala FMIC? Or just mounted somewhere in the back with a fan? Then again, any experience you have here is more than me.

Have you pursued methanol? IAT's make it harder to run full advance with pump gas and make the air charge less dense is all. If you spray meth, your effective octane goes up, helping timing. If you run E85 that helps negate the problem as well inside the engine. I also helped on a LSX build that ran twin 73mm turbo's non-intercooled. At anything over 20psi the IAT's were pegged past 250 degrees (max of the gauge) but with E85 and E98 it didn't much matter, still got full timing and made too much power to handle. We put a 1.4mm meth nozzle on each bank, and the IAT's dropped to below 120 degrees when spraying even after hard track runs in 100 degree weather and allowed for race gas to be used instead of alcohol. Maybe, you just need more methanol and less water in your mix.

I actually bought the 335i you see below in 2009 and totalled it since then. Back then it was FBO with meth, before E85 was being used regularly and the procede rev II was the only thing out. I've been waiting to find a good '09 E93 with black interior, PDC and nav to jump back into. Needless to say I'm pretty much ready to come back with all the new developments.

Back on topic- good luck if you go this route, it will be difficult to say the least. But I always like watching the crazy projects.

I've always done things the hard way. My 335i was a wrecked front end that slipped through the insurance with a clear title that I rebuilt from my garage all by myself. The only labor I paid was for paint.

Originally Posted by LostMarine

I didnt read the whole thing, but are you intending on running the extra water IC from existing fluid? If so, its probably more pain than its worth. HOWEVER, there are options for other ways to do it that would be easier install, and better benefits:

if I understand you correctly, the answer is no, A2W systems utilize a separate water circuit that require its own pump and 'radiator'. If done inline with an existing FMIC, it wouldn't need to run all the time and the current FMIC could do its normal thing.

Good find, that second link you posted is pretty close. I wasn't really intending on using an icebox but if there was room I don't think it would hurt, although my complexity is already through the roof. My real intention was to use an extra evaporator coil to cool the water by running the AC which pushes cold refrigerant through the evaporator coil, cooling the water to 30* temps. In Arizona, the humidity in the desert is quite low so water formation would be less of a concern than in more humid environments.

I figure, if I could replace the existing heat exchanger for the AC with a bigger and beefier version, plus put another heat exchanger in the driver side vent instead of a CAI cone, and put a fan on the back pulling air off the exchanger, I'd get a noticeable boost to the cooling capacity of the AC system. Also finding a way to bypass the in cabin evaporator some way would eliminate unnecessary cooling demands. That, combined with an appropriately sized A2W Intercooler that is inline with the current intercooler piping, taking the place of our existing upper chargepipe, should minimize any extra bends and drag to the system outside of pushing the air through the extra core. The existing FMIC, plus on demand A2W Cooling could be very beneficial in the arid summers of Arizona. Anyone thats driven in 120* weather on top of hot black asphalt in AZ know just how much that heat robs power and pulls timing like there is something wrong with the car.

This is an awful idea.... Besides all the extra plumbing, weight & potential for things to break/go wrong, you're going to need a power source and redesign lot. Like I said in your last thread, you're going to get better efficiency with less headaches on an already proven mod -- Meth. If you're really that desperate, just run a high concentration (even undiluted meth) pre-BOV/DVs to ensure proper atomization and have a trunk mounted tank. IF you don't tune for meth & just use it for cooling, it'll be a lot more effective since you'll never have to worry about water (your new coolants) temps leaving their efficiency range.

Combining E85 (cooler burn) with Meth (lower IATs) would be the probably be significantly more effective and significantly less costly then converting the car to air/water intercooling.

I dont think its that hard if you decide to run an a2w system, basically. its the same as the a2w s/c kits for the m3's. it depends on if i read it correctly, you want to replace the a2a, or supplement it? supplementing would be no use as it would be a pressure drop. but replacing it could be an option for testing, but it would be just that. i personally feel a2a is better for longer periods.

buy or copy one of the kits i posted. as for wher to mount the icebox, there are some engine bay coolers, and some trunk mount coolers. depends on what you want to do. I had a JLP for my Lightning, and loved it. but i can tell you, packed with 1lb ice and water would be fully melted by the end of a 1/4 mile run.. so you definitely need a heat exchanger, and water wetter.

Water does have a higher specific heat and transfers heat more readily than air, sure. I've said it before though, its not:

Air to air versus air to water its air to air versus air to water to water to air. There is another entire circuit in between when doing air to water. This is why you never get as cold with air to water unless you add in ice.

ATW is really only worth it if you A) have zero room for an front monunt ATA, or B) its a track car and you can keep the water in the tank very cold in between runs. But for platforms with limited room to run a big front mount they work very well, but the plumbing is quite a bit more involved. I have built quite a few cars with ATW's systems. I do not think the N54 is a good candidate for an ATW system.

ATW is really only worth it if you A) have zero room for an front monunt ATA, or B) its a track car and you can keep the water in the tank very cold in between runs. But for platforms with limited room to run a big front mount they work very well, but the plumbing is quite a bit more involved. I have built quite a few cars with ATW's systems. I do not think the N54 is a good candidate for an ATW system.

Well, depending on how I feel I'm prepared to prove everyone wrong or at least gather some IAT data in the mean time

I dont think its that hard if you decide to run an a2w system, basically. its the same as the a2w s/c kits for the m3's. it depends on if i read it correctly, you want to replace the a2a, or supplement it? supplementing would be no use as it would be a pressure drop.

What is the formula or rule of thumb when calculating impact of pressure drop? Also, I wonder if there would be a way to build a collector post A2W Intercooler to gather the pooling water with a drain at the bottom?

EDIT:

Also I noticed this quote:

The core is downstream of the compressor and actually improves the cars air conditioning while in use.

So, adding extra heat into the refrigerant from the cooling core IMPROVES the AC system? Can someone explain how this is possible? Perhaps it has something to do with the Liquid-> Gas transition and forcing of the refrigerant to become hotter, and gather more cooling from the a2w heat exchanger at the front of the car? I know that the compressors job is actually to make the refrigerant hot so this can happen, which is why it is compressed to create more gaseous heat.

Well, depending on how I feel I'm prepared to prove everyone wrong or at least gather some IAT data in the mean time

This N54 platform confuses me, just like with the fuel systems. Everyone things they are reinventing something. If you want to try to prove years worth of RD and whats already been proven by other platforms right or wrong, by stuffing heat exchangers, tank, lines, etc etc. For what maybe a couple degrees cooler IAT, maybe no gains at all, maybe higher IAT's. Then go for it. But when something has been done on multiple platforms, for years, the best advice is just learn from other people already doing it.

This N54 platform confuses me, just like with the fuel systems. Everyone things they are reinventing something. If you want to try to prove years worth of RD and whats already been proven by other platforms right or wrong, by stuffing heat exchangers, tank, lines, etc etc. For what maybe a couple degrees cooler IAT, maybe no gains at all, maybe higher IAT's. Then go for it. But when something has been done on multiple platforms, for years, the best advice is just learn from other people already doing it.

Comparing pretty much any properly setup A2W setup running AC refrigerant, compared to a straight, properly setup A2A setup with no meth on either, I think the differences are quite large, wouldn't you agree? A2A just doesn't cool the same way. I mean when you got 120* ambient air going across your FMIC in AZ, what exactly are we really achieving with A2A? Not a lot. Anyone live in AZ? Care to chime in on this? AZ folks NEED an external cooling source that hot air blowing across my FMIC just can't keep up with. Even if the inter cooler core was small, minimizing pressure drop, and the evaporator was huge, which you could do, you have the power of the refrigerant pulling some extra weight that a FMIC just can't do alone, not to mention there is nothing stopping you from injecting meth with an A2W setup as well.

I'm not saying people haven't done it with lackluster results, and I believe their results as I could very well come out at the end and say, its not worth it. Its very possible. But I'm willing to throw some money away for an attempt to obtain lower IAT. You can say that FMIC keeps up, but it doesn't here in the desert. In the summer here, nobody goes outside. And if you do, its 5am in the morning or you are on your way to get into your car, which burns you every where you touch it if its outside, and requires you wrap whatever trash, mail, paper over your steering wheel from being literally burned.

You are missing the bottom line. The entire point of upgrades are benefit compared to modifications required. The amount of modifications and things you would have to add to the car is not in line with the possible IAT reductions you may get, which would add very little benefit in street driving. A meth kit on the other hand, gives you a very big benefit to modification ratio. If you are bored and just want to try something, then by all means go for it. But people have done all this testing before, its all out there on the internet for you to find.

You are missing the bottom line. The entire point of upgrades are benefit compared to modifications required. The amount of modifications and things you would have to add to the car is not in line with the possible IAT reductions you may get, which would add very little benefit in street driving. A meth kit on the other hand, gives you a very big benefit to modification ratio. If you are bored and just want to try something, then by all means go for it. But people have done all this testing before, its all out there on the internet for you to find.

I don't disagree that the cost may be high and that meth is a better bang for the buck solution to the IAT situation. AZ is all freeways. Everything is 30 minutes away or more. I routinely drive 1.5 hours per day sometimes 2.5 hours on a Friday to work related areas. Its all freeway. In the summer, one pull in third gear would heat soak me. My street driving in AZ is all freeway, 99%. Its like that for most folks in the Phoenix Valley. 101, 17,i10, 60, 202, 51. These freeways I use 4 or 5 out of six of them each day. And anyone going from west valley to east valley or vice versa does as well. Our local roads that go by our houses are 5 lanes across with the suicide lane(used in rush our for an extra lane in certain times), and avg speed is about 50-60 and everything is straight as far as the eye can see. Street driving here isn't anything like street driving in say NYC or LA for example.

I personally see a naturally cooler IAT healthier than injecting methanol. I've ran a snow system before, its all well and good but I'd rather stray away from it once our HPFP is resolved and just run e85.

Comparing pretty much any properly setup A2W setup running AC refrigerant, compared to a straight, properly setup A2A setup with no meth on either, I think the differences are quite large, wouldn't you agree? A2A just doesn't cool the same way. I mean when you got 120* ambient air going across your FMIC in AZ, what exactly are we really achieving with A2A?

It's not that much different that CA or FL, if anything the atmosphere in AZ is the best because it's a dry heat, which is easier to reduce IATs vs. hot, humid air like in FL/GA/etc. If you look at any of the N54 datalogs with IATs being monitored, your IATs are really only going to climb when going WOT. When cruising about, any passive airflow will be effectively reduce IATs with an Air/Air setup.

Air/Water is best suited for cars that are focused on short, high stress burst (1/4 miles, 1 mile pulls, etc.), where the water has a more effective cooling capability & there is no concern for the water (coolant) temps leaving their effective cooling range -- this can easily be fought off with a water/ice chest. Air/Air is best for cars actually being driven (street cars, track cars, etc) where there is an abundance of passive airflow that will constantly be cooling.

While air/air FMICs can be heatsoaked, if you stop driving aggressively the core will be able to return into it's efficiency range. Meanwhile once an air/water coolant's temps leave it's efficiency range, the only way to become effective at cooling again is A) swapping out the coolant (will require stopping, draining your coolant tank & refilling with ice and/or new water + chemicals) or B) turning the car off.

Another thing you need to take into account, with an air/water setup you're also susceptible to your ambiat temps. If the coolant is sitting in a tank, under the hood of a car & the sun's beating down it while it's 95+ outside, do you really think that the coolant in the air/water is going to remain in it's effectiveness range that long once you start beating on it? Absolutely not, chances are if you make some pulls the car the DME will start reducing timing as your IATs continue to increase. While you might heatsoak after one 3rd gear pull with your FMIC, at least you can drive & the core will cool off.

It's not that much different that CA or FL, if anything the atmosphere in AZ is the best because it's a dry heat, which is easier to reduce IATs vs. hot, humid air like in FL/GA/etc. If you look at any of the N54 datalogs with IATs being monitored, your IATs are really only going to climb when going WOT. When cruising about, any passive airflow will be effectively reduce IATs with an Air/Air setup.

You've clearly never been to AZ in the summer. We get 110* in september. Come to AZ in the summer and you wouldn't say what your saying now, lol.

While air/air FMICs can be heatsoaked, if you stop driving aggressively the core will be able to return into it's efficiency range.
Meanwhile once an air/water coolant's temps leave it's efficiency range, the only way to become effective at cooling again is A) swapping out the coolant (will require stopping, draining your coolant tank & refilling with ice and/or new water + chemicals) or B) turning the car off.

You're telling me I should "Stop driving agressively" as your solution to a2a and you're also saying I should, "Stop driving" with a2w. Whats the difference? A2A Gets heat soaked very quickly in arizona, I won't say it again. Stop driving agressively might as well mean pull my car over. The IAT's are going to be $#@!in high even if I wait a few minutes. If you want, I can show you sold old logs of mine and its absurd. You're also saying I should pull my car over with A2W? Thats the point of the AC Evaporator. AFTER my pull, my TB inlet temps will still be colder than your A2A inlet temps on its first run. So what your saying doesn't really apply here.

Another thing you need to take into account, with an air/water setup you're also susceptible to your ambiat temps. If the coolant is sitting in a tank, under the hood of a car & the sun's beating down it while it's 95+ outside, do you really think that the coolant in the air/water is going to remain in it's effectiveness range that long once you start beating on it? Absolutely not, chances are if you make some pulls the car the DME will start reducing timing as your IATs continue to increase. While you might heatsoak after one 3rd gear pull with your FMIC, at least you can drive & the core will cool off.

AC Evaporator. This is the entire point of my thread and makes everything you're saying matter much less. Evaporator will cool the coolant to 30*.

You're saying that only with a2a will driving cool down the core? Thats also incorrect. A2W has a heat exchanger right in front of the radiator. Driving will cool the A2W heat exchanger, just as your FMIC would, and cool the water circuit for the A2W. I think perhaps you mean well but what you're telling me is not scientific, its just off the top of your head. Where does your A2W experience come from if you don't mind me asking?

Miami is the second hottest weather city in the United states, with an annual average daily temperature of 75.6 degrees.Despite that fact, the temperature in Miami has only reached 100 degrees once since 1895. The hottest temperature ever recorded in Miami, Florida is exactly 100 degrees, which occurred on July 21, 1942.

I wonder how much boost people were runnin back in good ole '42?

Miami's temperature records are measured in the 90's. Arizona's are measured in the 100's and 110's.

Phoenix September 2012:

Phoenix had 85 days of temperatures over 100 during the three-month period and 108 so far this year.But the area had more than its fair share of 110-degree days so far this year -- 23 of them, more than the average of 18 but 10 fewer than in 2011.

We get days over 100 even outside of summer, you don't apparently even see 100. Some days I WISH it was only 100. In 2011, we had 33 days OVER 110*. Most people don't even know what 120* feels like. I drive on it just about every year, for 1-2 hours PER day, on the freeways, which are well generally well constructed, smooth roads, virtually no potholes and typically open range driving averaging 75-80mph and still I put that much time on the freeway, this is not me sitting parked in stop and go traffic eating up that driving time.